1. Field of the Invention
Most electronic appliances include semiconductor devices. The semiconductor devices include electronic elements such as a transistor, a resistor and a capacitor. The electronic elements are integrated on a semiconductor substrate after being designed for performing a partial function of the electronic appliances. For example, electronic appliances such as a computer or a digital camera include a memory chip for storing information and a processing chip for controlling information. The memory chip and the processing chip include the electronic elements integrated on the semiconductor substrate.
2. Description of the Related Art
In the meantime, the semiconductor devices are required to be highly integrated to meet a good performance and a low price which users expect. Conventionally, for high integration, a method of decreasing sizes of the electronic elements constituting the semiconductor devices was adopted. However, due to various technical limitations (in particular, a photolithography technical limit) during a manufacturing process of the semiconductor device, the method of decreasing sizes of the electronic elements has slowly progressed. Accordingly, a new method of forming a semiconductor device which can overcome the above technical limitations is needed to achieve the required high integration of the semiconductor device.
A double patterning technique is recently introduced as a technique that may satisfy the above technical requirement. The double patterning technique is a technique that mask patterns to form n number of patterns which are alternately arranged and are independently formed through two patterning steps. A first mask pattern and a second mask pattern are used as masks to form respective 2i-th patterns and 2i+1-th patterns (i=0˜n/2). However, according to this method, the 2ith patterns and the 2i+1-th patterns may be formed to have different line widths and that may cause even-odd failure which degrades uniformity of an electrical characteristic of a semiconductor device.